The invention relates to power transmission belts having an engineered surface and more particularly, to power transmission belts having an engineered surface comprising a region having a non-woven material and a fiber loaded compression layer.
It is known in the art to make power transmission belts from elastomeric materials having an embedded tensile member. The belts may describe a multi-rib, toothed or v type profile. The belts run in pulleys having a matching profile.
It is known that the rib flank surfaces of V and multi-v rib belts are subject to sliding wear, temperature extremes, normal and frictional forces that cause belt noise, rib surface sloughing, slipping, and chatter. It is also known that power transmission capacity and belt longevity are functions of several factors, including the type of material contacting the pulley surfaces. These are currently addressed by incorporating a high loading of various fibers into the mix of the undercord materials. These fibers, or portions of them, are exposed when the V profile is cut or ground to form the belt from the cured belt slab. The resulting surface is a combination of the base polymer and exposed fibers. This technique is limited with regard to an engineering approach for composite design, and/or controlling friction, noise, and slippage. It also creates a stiff structure that resists bending, which can contribute to belt rib cracking and shortened belt life.
Representative of the art is U.S. Pat. No. 4,892,510 (1990) to Matsuoka which discloses a v-ribbed belt having a surface layer comprising a non-woven fabric at the outer surface vulcanized to ribs solely made of rubber.
Also representative of the art is U.S. Pat. No. 5,536,214 (1996) to Akita et al. which discloses a power transmission belt having non-woven fabric on the inside of the belt body on a plurality of the grooves.
Also representative of the art is U.S. Pat. No. 4,956,036 (1990) to Sedlacek which discloses a discontinuous fiber loaded compressive layer in a multi-ribbed belt. The belt is ground to create the required rib profile, thereby exposing the fibers. The elastomeric body portion is loaded with fiber preferably from about 0.5 to 20% by volume, with preferred loading at 3% by volume.
What is needed is a power transmission belt having a non-woven pulley engaging surface and fiber loaded compressive layer. What is needed is a power transmission belt having a non-woven pulley engaging surface and fiber loaded compressive layer and a multi-ribbed profile. The present invention meets these needs.
The primary aspect of the invention is to provide a power transmission belt having a non-woven pulley engaging surface and fiber loaded compressive layer.
Another aspect of the invention is to provide a power transmission belt having a non-woven pulley engaging surface and fiber loaded compressive layer and a multi-ribbed profile.
Other aspects of the invention will be pointed out or made obvious by the following description of the invention and the accompanying drawings.
The invention comprises a belt having a region comprising a non-woven material on a pulley engaging surface. The non-woven region has a random coverage of the non-woven material to reduce natural frequency harmonics, control frictional characteristics, permeation and thermal resistance. The non-woven may comprise a combination of softwood and hardwood pulp, as well as synthetic fibers applied in a random matrix to a body having a fiber loading.